Motorcycle front brake master cylinder assembly

ABSTRACT

A brake assembly has a lever configured to press a knee against a pushrod of a piston of a master cylinder assembly. The knee is configured to receive removable inserts that allow a user to modify the angle at which the lever activates the master cylinder assembly. The master cylinder assembly can include protrusions on the outer surface of the cylinder to protect the cylinder from impact damage.

INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS

Any and all applications for which a foreign or domestic priority claimis identified in the Application Data Sheet as filed with the presentapplication are hereby incorporated by reference under 37 CFR 1.57.

BACKGROUND

Field

The present disclosure relates to generally to hydraulic brake systemsand, in particular, to a handbrake system for a motorcycle, dirt bike,or ATV.

Description of Related Art

Hydraulic brake systems often use an incompressible fluid to generateleverage for squeezing a brake pad against a rotor. In a hydraulichandbrake system, when the brake lever is squeezed, a pushrod exertsforce on a piston in the master cylinder. Movement of the piston in themaster cylinder seals off the bypass or compensation port, trappingfluid ahead of the piston. Further movement of the piston increases thepressure of the entire hydraulic system, forcing fluid through thehydraulic lines toward one or more calipers where the fluid acts uponone or two caliper pistons sealed by one or more seated O-rings thatprevent leakage of the fluid.

Subsequent release of the brake lever allows a return mechanism (e.g., aspring in the master cylinder assembly) to return the master piston backinto its rest position. This return action first relieves the hydraulicpressure on the caliper, then applies suction to the brake piston in thecaliper assembly, moving it back into its housing and allowing the brakepads to release the rotor.

SUMMARY

The systems, methods and devices described herein have innovativeaspects, no single one of which is indispensable or solely responsiblefor their desirable attributes. Without limiting the scope of theclaims, some of the advantageous features will now be summarized.

An aspect of the present invention is a lever configured to compress apushrod of a master cylinder assembly of a brake assembly, the leverhaving a removable insert that allows the leverage between the lever andthe pushrod to be changed. In some aspects, the orientation of theremovable insert within the lever can be changed to change the leveragebetween the lever and the pushrod. The brake assembly may include morethan one inserts, with some, all, or none of the inserts providing adifferent leverage between the lever and the pushrod. In some aspects,the lever includes a knee portion, a handle portion, and a set screwthat allows the position of the handle relative to the knee to beadjusted. In some aspects, the master cylinder assembly is coupled to aperch that secures the brake assembly to a handlebar of a motorcycle orATV. In some aspects, the perch is positioned to overlap longitudinallywith a pivot that connects the lever to the master cylinder assembly. Incertain aspects, the master cylinder assembly includes protrusions onthe outer surface of the cylinder to protect the cylinder from damagewithout increasing the entire wall thickness of the cylinder. In someaspects, the master cylinder assembly includes a guard that has a flangehaving a low clearance with a portion of the lever, with the flangeoperating as a wiper to remove debris from the lever as the lever isoperated. In some aspects, a collar is inserted between the perch andthe handlebar to allow the brake assembly to rotate about the handlebarduring impact, thereby protecting the brake assembly from damage.

BRIEF DESCRIPTION OF THE DRAWINGS

Throughout the drawings, reference numbers can be reused to indicategeneral correspondence between reference elements. The drawings areprovided to illustrate example embodiments described herein and are notintended to limit the scope of the disclosure.

FIG. 1 is a top view of an embodiment of a hydraulic brake assembly.

FIG. 2 is a rear cross-sectional view of the master cylinder assemblyportion of the brake assembly of FIG. 1.

FIG. 3 is a upwardly-angled front view of the master cylinder assemblyof FIG. 2.

FIG. 4 is an isometric view of the guard and master cylinder assembly ofFIG. 2.

FIG. 5A is an isometric view of the knee and lever portion of the brakeassembly of FIG. 1.

FIG. 5B is an assembly view of the knee and lever portion of FIG. 5A.

FIG. 6 is an end view of the guard and master cylinder assembly of FIG.4.

FIGS. 7A and B show front and side views of inserts having differentcavity configurations.

DETAILED DESCRIPTION

Embodiments of systems, components and methods of assembly andmanufacture will now be described with reference to the accompanyingfigures, wherein like numerals refer to like or similar elementsthroughout. Although several embodiments, examples and illustrations aredisclosed below, it will be understood by those of ordinary skill in theart that the inventions described herein extends beyond the specificallydisclosed embodiments, examples and illustrations, and can include otheruses of the inventions and obvious modifications and equivalentsthereof. The terminology used in the description presented herein is notintended to be interpreted in any limited or restrictive manner simplybecause it is being used in conjunction with a detailed description ofcertain specific embodiments of the inventions. In addition, embodimentsof the inventions can comprise several novel features and no singlefeature is solely responsible for its desirable attributes or isessential to practicing the inventions herein described.

Certain terminology may be used in the following description for thepurpose of reference only, and thus are not intended to be limiting. Forexample, terms such as “above” and “below” refer to directions in thedrawings to which reference is made. Terms such as “front,” “back,”“left,” “right,” “rear,” and “side” describe the orientation and/orlocation of portions of the components or elements within a consistentbut arbitrary frame of reference which is made clear by reference to thetext and the associated drawings describing the components or elementsunder discussion. Moreover, terms such as “first,” “second,” “third,”and so on may be used to describe separate components. Such terminologymay include the words specifically mentioned above, derivatives thereof,and words of similar import.

Overview

FIG. 1 depicts a top view of a non-limiting, illustrative embodiment ofa brake assembly 100. The brake assembly 100 can include a lever 200, aknee 300, a master cylinder assembly 400, and a guard 500. The lever 200can be coupled to the knee 300 by a pin 110. In some variants, the brakeassembly may not include a pin 110, with the lever 200 and the knee 300being portions of a continuous, unitary structure. The pin 110 can bemany different types of a fastener (e.g., a bolt, a weld). The lever 200can be adapted to rotate about the pin 110. In some embodiments, thelever 200 can be restricted from rotating about the pin 110.

The knee 300 can be coupled to the master cylinder assembly 400 by apivot 120. The pivot 120 can be many different types of a fastener(e.g., a bolt, a screw, a pin). The knee 300 can be adapted to rotateabout the pivot 120.

The guard 500 can be secured to the master cylinder assembly 400 by afastener 130. The fastener 130 can be many different types of a fastener(e.g., a bolt, a weld). In some variants, the guard 500 can be formed asa continuous, unitary structure of another component of the brakeassembly 100 (e.g., the master cylinder assembly 400, the knee 300, thelever 200).

The master cylinder assembly 400 may include or be coupled to a perch410 that is adapted to secure the brake assembly 100 to a secondarystructure (e.g., handlebar). The brake assembly 100 can be configured sothat a brake is applied when the lever 200 is moved in a first direction(e.g., toward the handlebar). The brake assembly 100 can be configuredso that the brake is released when the lever 200 is moved in a seconddirection (e.g., away from the handlebar). The brake assembly 100 can bearranged so that the brake is applied when the lever 200 rotates in afirst direction about the pivot 120, and the brake is released when thelever 200 rotates in a second direction about the pivot 120, with thefirst and second directions being opposite directions of rotation aroundthe pivot 120.

The brake assembly 100 can be arranged so that the lever 200 pushes theknee 300 toward the master cylinder assembly 400 when the lever 200moves toward the perch 410. As shown in FIG. 1, the brake assembly 100can include an adjustment element 140. The adjustment element 140 can beadapted to allow adjustment of the rest position of the lever 200relative to the knee 300. The adjustment element 140 can be coupled tothe lever 200 by a coupling element 202 of the lever 200. The adjustmentelement 140 can engage a fin 310 on the knee 300. In some variants, theorientation of the adjustment element 140 can be flipped so that theadjustment element 140 couples to the knee 300 and engages a “fin-like”structure (not shown) on the lever 200.

Referring to FIG. 1, the adjustment element 140 can serve as anintervening structure through which the lever 200 can move the knee 300toward the master cylinder assembly 400. In some embodiments, the lever200 can move the knee 300 toward the master cylinder assembly 400through a non-adjustable portion of the lever 200.

Master Cylinder Assembly

FIG. 2 depicts a rear cross-sectional view of a non-limiting,illustrative embodiment of the master cylinder assembly 400. The mastercylinder assembly 400 can include a reservoir 420, a cylinder 430, and apiston 440. The reservoir 420 can be adapted to contain a liquid 421(e.g., brake fluid). The cylinder 430 can surround a channel 432 thathas a longitudinal axis 434. The channel 432 can be substantiallycylindrical and surround the piston 440. The channel 432 can be adaptedto have a small clearance between the cylinder 430 and the piston 440.The master cylinder assembly 400 can include an inlet port 422 throughwhich the reservoir 420 can communicate with the channel 432. The mastercylinder assembly 400 can include a compensating port 424 through whichthe reservoir 420 can communicate with the channel 432. The mastercylinder assembly 400 can include an outlet port 426 through which thechannel 432 can communicate with a hydraulic brake line (not shown).

The master cylinder assembly 400 can be arranged so that the piston 440moves within the channel 432 along the longitudinal axis 434. The piston440 can include, or be coupled with, a pushrod 442. The piston 440 canbe coupled to the pushrod 442 by a flexible joint (not shown) thatallows the pushrod 442 to articulate in one or more directions relativeto the piston 440. The master cylinder assembly 400 can include asealing element 446 that surrounds the pushrod 442. The sealing element446 can be adapted to block the liquid 421 from flowing past the pushrod442, as shown in FIG. 2.

The master cylinder assembly 400 can include a return spring 444. Thereturn spring 444 can be arranged to be co-axial with the channel 432.The return spring 444 can be disposed between the piston 440 and thecylinder 430. As shown in FIG. 2, the return spring 444 can be disposedbetween a distal end surface 436 of the channel 432 and an end 441 ofthe piston 440. The return spring 444 can be configured to compress whena compression force is applied to the pushrod 442, thereby allowing thepiston 440 to move toward the distal end surface 436 of the channel 432.The return spring 444 can be configured to supply a restoring force suchthat the piston 440 moves away from the distal end surface 436 of thechannel 432 when the compression force applied to the pushrod 442 isreduced. The master cylinder assembly 400 can be configured such thatmovement of the piston 440 toward the distal end surface 436 of thechannel 432 increases the pressure of the liquid 421 in the outlet port426 and in the downstream hydraulic brake line (not shown). The mastercylinder assembly 400 can be configured such that movement of the piston440 away from the distal end surface 436 of the channel 432 decreasesthe pressure of the liquid 421 in the outlet port 426 and in thedownstream hydraulic brake line (not shown). The brake assembly can beconfigured so that an increase in the pressure of the liquid 421 in theoutlet port 426 activates the brake. The brake assembly can beconfigured so that a decrease in the pressure of the liquid 421 in theoutlet port 426 releases the brake. As shown in FIG. 2, the piston 440has moved toward the distal end surface 436, thereby increasing thepressure of the liquid 421 in the outlet port 426 and activating thebrake.

FIG. 3 shows an upwardly-angled front view of the master cylinderassembly 400. The master cylinder assembly 400 can be secured to a perch410. As shown in FIG. 3, the perch 410 can form a unitary structure withthe master cylinder assembly 400. The perch 410 can be aligned with thepivot 120. In other words, a line that passes through the pivot 120 andis substantially perpendicular to the longitudinal axis 434 of thechannel 432 can pass through at least a portion of the perch 410. Asbest seen in FIG. 1, the perch 410 can have a width 105, which isdefined by an inboard position 101 of a first lateral surface of theperch and an outboard position 103 of a second lateral surface of theperch 410. The pivot 120 can be located between the first and secondlateral surfaces of the perch 410. The perch 410 can be located inboardof the pivot 120 (e.g., toward the reservoir 420). The perch 410 can belocated outboard of the pivot 120 (e.g., away from the reservoir 420).Positioning the perch 410 to be approximately in line with the pivot 120allows standard “finger/pocket” positioning on the lever 200, whichallows increased leverage on the lever 200. As seen in FIG. 1, the“finger/pocket” can have a leverage distance 107 with respect to thepivot 120. Although the “finger/pocket” positioning could also beachieved by sliding outboard an assembly having an inboard perchplacement, the handlebar has a limited space available for mounting thebrake assembly 100. For example, the handlebar is curved and mustaccommodate other components such as a handgrip, thereby limiting thespace available for sliding the brake assembly 100 along the handlebar.

As shown in FIG. 3, the outer surface of the cylinder 430 may includeone or more protrusions 452. The protrusion 452 can be in the form of araised ridge that runs substantially parallel to a longitudinal axis 434of the cylinder 430. However, the protrusion 452 need not be parallel tothe longitudinal axis 434. The protrusion 452 may have a form other thanlinear (e.g., sinusoidal, zig-zag, punctate). In some variants, theprotrusion 452 can be adapted to protect the cylinder 430 from becomingdamaged due to impact of the cylinder 430 with an outside structure,such as, for example, flying debris (e.g., a rock). As discussed above,the clearance between the piston and the cylinder 430 can be small,making it likely that any deformation of the cylinder 430 can interferewith the piston moving back and forth within the cylinder 430. Theprotrusion 452 can be adapted to shield the outer surface of thecylinder 430 from coming into contact with an outside structure, therebyprotecting the cylinder 430 from a deformation that could renderinoperable the master cylinder assembly 400. The protrusion 452 can beadapted to help prevent rock damage to the cylinder 430 withoutincreasing the entire wall thickness of the cylinder 430, therebyrequiring a bigger rock to damage and render inoperable the cylinder430.

FIG. 4 shows an isometric view of a non-limiting, illustrativeembodiment of the master cylinder assembly 400. The perch 410 cansurround an opening 412 through which a secondary structure can bepassed. In some variants, the opening 412 can be adapted to allow ahandle bar to be passed through the opening 412. The perch 410 caninclude a base portion 414 that partially circumferentially surroundsthe opening 412. The perch 410 can include a cap portion 416 thatpartially circumferentially surrounds the opening 412. The perch 410 caninclude one or more clamp elements 418 that are configured to couple thecap portion 416 to the base portion 414. The clamp element 418 can bemany different types of a fastener (e.g., a threaded screw). The perch410 can be configured to allow the cap portion 416 to be completelyremoved from the base portion 414. The perch 410 can be adapted so thatthe cap portion 416 remains coupled to the base portion 410 when theclamp element 418 is at its fully opened configuration.

The perch 410 can include one, none, or more than one liners 411 a,b.The liners 411 a,b can be disposed immediately adjacent to the opening412. The perch 410 can include a cap liner 411 a and/or a base liner 411b. The liners 411 a,b can be fused to the perch 410. In some variants,the liners 411 a,b can be removable inserts. In at least one embodiment,the cap liner 411 a can be a continuous, unitary structure with the baseliner 411 b. For example, the cap liner 411 a and the base liner 411 bcan be in the form of a single liner that completely surrounds theopening 412, such as, for example, an annular sleeve. In some variants,the cap liner 411 a and the base liner 411 b can be in the form of asingle liner that completely or only partially surrounds the opening412, such as, for example, a slotted ring.

The liners 411 a,b can comprise a material (e.g.,polytetrafluoroethylene, nylon) that reduces the friction between theperch 410 and the secondary structure that is passed through the opening412. The liners 411 a,b can be adapted so that there is more consistentcontrol of adjusted slippage of the brake assembly 100, allowing thetightness to be adjusted so that the brake assembly 100 will stillrotate when impacted. The liners 411 a,b can be adapted to allow thebrake assembly 100 to rotate around the handlebar when impacted, therebyhelping to protect the brake assembly 100 from damage resulting from animpact.

In some variants, the perch 410 is mounted to a secondary structure(e.g., handlebar) by loosening the clamp element 418 to increase anouter dimension of the opening 412, passing the secondary structurethrough the opening 412, and tightening the clamp element 418 to reducethe outer dimension of the opening 412. The perch 410 can be mounted byremoving the cap portion 416 from the perch 410, seating the baseportion 414 on the handlebar, reconnecting the cap portion 416 to theperch 410, and tightening the clamp element 418 to reduce an outerdimension of the opening 412, thereby securing the perch 410 to thehandlebar. In some variants, the liners 411 a,b can be a sleeve orbroken ring that is positioned on the handlebar before mounting theperch 410 to the handlebar. In some embodiments, the liners 411 a,b areinserts that are positioned within the perch 410 before, after, orduring mounting the perch 410 to the handlebar.

As shown in FIG. 4, the pushrod 442 and sealing element 446 can extendtoward the knee 300 (shown in FIG. 1) of the brake assembly. The pushrod442 and sealing element 446 can be configured to articulate in anydirection (e.g., toward the perch 410, toward the guard 500, toward alateral surface 419 of the master cylinder assembly 400).

Knee

FIG. 5A depicts an isometric view of the knee 300 and lever 200. Theknee 300 can include an extension 302 adapted to engage at least aportion of the pushrod 442. The extension 302 can include apiston-facing surface 304. The piston-facing surface 304 can beconfigured to compress against the pushrod 442 as the lever 200 isrotated about the pivot 120 toward the extension 302.

The piston-facing surface 304 can be adapted to receive an insert 306.For example, the piston-facing surface 304 can include a recess 301(shown in FIG. 5B) adapted to receive the insert 306. The insert 306 caninclude a cavity 308. The cavity can have a depth 305 and be located ata radius 307 from the pivot 120. The cavity 308 can be configured toreceive at least a portion of the pushrod 442. As mentioned above, thepushrod 442 can articulate with respect to the piston 440, allowing thepushrod 442 to maintain contact with the cavity 308 as the knee 300swings in an arc about the pivot 120.

Referring to FIGS. 7A and B, the brake assembly 100 can include aplurality of inserts 306, with some, all, or none of the inserts 306having a different depth 305 and/or distance 309 from an edge of theinsert 306. Changing the distance 309 of the cavity 308 from the edge ofthe insert 306 will result in a change in the radius 307. The depth 305and/or radius 307 of the insert 306 can be selected to produce a desiredleverage ratio between the lever 200 and the pushrod 442. In somevariants, the depth 305 and/or radius 307 of the cavity 308 can bemodified to accommodate rider preference and/or the course conditions.In some variants, as the distance 309 is increased, the depth 308 of thecavity can decrease to accommodate the change in angle at which thepushrod 442 engages the insert 306. The pushrod 442 can articulate toallow the pushrod 442 to engage one or more cavities 308 that have adifferent depth 305 and/or radius 307.

The insert 306 and the piston-facing surface 304 can be configured toallow the insert 306 to be inserted into the extension 302 in adifferent orientation. For example, the insert 306 can be adapted fitinto the extension 302 when the insert 306 is oriented in twoorientations that are 180 degrees apart. As illustrated in FIG. 5A, insome embodiments the insert 306 can be rotated 180 degrees in the planeof the piston-facing surface 304 so that the cavity 308 still faces thepushrod 440 but has a different radius 307 with respect to the pivot120. In this way, three inserts can be adapted to make six leverageratios. The insert 306 can also include a second cavity 308 on theopposing surface of the insert 306, allowing a user to flip the insert306 over so that the cavity 308 on the opposing surface now faces thepushrod 442. The cavity 308 on the opposing surface can have a depth 305and/or radius 307 that is different from the cavity 308 on the othersurface of the insert 306.

FIG. 5B depicts an assembly view of a non-limiting, illustrativeembodiment of the knee 300, showing how the insert 306 can be configuredto fit into a recess 301 of the knee 300. The knee 300 can include aport 303 that facilitates removal of the insert 306 from the knee 300.As illustrated in FIG. 5B, the port 303 can be a hole that allows a pinto be inserted through the port 303 and push the insert 306 out of therecess 301.

The knee 300 can also include a stop 320. The stop 320 can be configuredto contact an abutment 450 (shown in FIG. 6). As discussed below, thebrake assembly can be configured to allow the contact point between thetop 320 and the abutment 450 to be adjusted.

Lever

Referring to FIG. 5A, the lever 200 can be coupled to the adjustmentelement 140 by the coupling element 202. The coupling element 202 caninclude an internal thread that mates with an external thread on theadjustment element 140. The brake assembly 100 can include a biasingelement 124 that can be configured to compress the adjustment element140 against a fin 310 (shown in FIG. 1). The biasing element 124 can be,for example, a torsion spring that surrounds the pin 110. The adjustmentelement 140 can include a head 142 that has one or more grooves 144 thatare configured to receive the fin 310. The head 142 can include two ormore grooves 144 that are substantially perpendicular to one another.The head 142 can include two grooves 144 that are not substantiallyperpendicular to one another. For example, the head 144 can include fourgrooves that are 45 degrees apart from one another.

The adjustment element 140 can be a “no-tool” adjuster. The position ofthe adjustment element 140 relative to the lever 200 or knee 300 can beadjusted by pushing the lever 200 against the biasing element 124 tofree the head 142 from the fin 310, thereby allowing the head 142 to beset to a different position relative to the lever 200. As illustrated inFIG. 5A, the adjustment element 140 can be adjusted to a differentposition by turning the head 142 of the adjustment element 140 after thehead 142 has been freed from the fin 310, thereby changing the positionof the head 142 relative to the coupling element 202. In some variants,turning the head 142 can cause an external thread on the adjustmentelement 140 to advance along an internal thread of the coupling element202, thereby causing the head 142 to move longitudinally toward or awayfrom the coupling element 202. The biasing element 124 can be configuredto compress the groove 144 against the fin 310, thereby blocking theadjustment element 140 from moving when the lever 200 is not extendedagainst the biasing element 140. Further details of the lever arediscussed in U.S. Pat. No. 7,921,747, entitled “COLLAPSIBLE CONTROLLEVER,” filed on Jan. 5, 2005, and which is incorporated herein byreference in its entirety.

Guard

FIG. 6 is a side view of the master cylinder assembly 400 and the guard500. The guard 500 can include one or more flanges 502. As illustratedin FIG. 1, the flange 502 can cover at least a portion of the knee 300.The clearance between the flange 502 and the knee 300 can be small,allowing the flange 502 to act as a wiper for removing mud or otherdebris from the knee 300, for example, as the knee 300 rotates about thepivot 120. The clearance can be between about 0.1 mm and about 5 mm,between about 0.5 mm and about 3 mm, and between about 1 mm and about 2mm. In some variants, the knee 300 can be exposed from the guard 500when the brake is applied, resulting in debris accumulating on the knee300 and/or lever 200. When the brake is released, the knee 300 movesback under the guard 500 and the flange 502 wipes debris off of the knee300 and/or lever 200, thereby keeping the knee 300 and/or lever 200clear of debris.

As discussed above, the brake assembly 100 can include an abutment 450that engages a stop 320 on the knee 300. The abutment 450 can bepositioned on the master cylinder assembly 400 or on the guard 500. Theabutment 450 can include a cap surface 454 that contacts the stop 320.The cap surface 454 can be adjustable to allow the brake lever assembly100 to be tuned to rider preference and/or course conditions. Forexample, the cap surface 454 can be a threaded screw (e.g., a set screw)that can be advanced longitudinally away from or toward the mastercylinder assembly 400, thereby changing the rotational angle of the knee300 at which the stop 320 contacts the cap surface 454. In somevariants, the cap surface 454 can be adjusted to accommodate the pushrod442 having a longer or shorter length and/or to accommodate the cavity308 having a greater or lesser depth 305.

CONCLUSION

It should be emphasized that many variations and modifications may bemade to the herein-described embodiments, the elements of which are tobe understood as being among other acceptable examples. All suchmodifications and variations are intended to be included herein withinthe scope of this disclosure and protected by the following claims.Moreover, any of the steps described herein can be performedsimultaneously or in an order different from the steps as orderedherein. Moreover, as should be apparent, the features and attributes ofthe specific embodiments disclosed herein may be combined in differentways to form additional embodiments, all of which fall within the scopeof the present disclosure.

Conditional language used herein, such as, among others, “can,” “could,”“might,” “may,” “e.g.,” and the like, unless specifically statedotherwise, or otherwise understood within the context as used, isgenerally intended to convey that certain embodiments include, whileother embodiments do not include, certain features, elements and/orstates. Thus, such conditional language is not generally intended toimply that features, elements and/or states are in any way required forone or more embodiments or that one or more embodiments necessarilyinclude logic for deciding, with or without author input or prompting,whether these features, elements and/or states are included or are to beperformed in any particular embodiment.

Moreover, the following terminology may have been used herein. Thesingular forms “a,” “an,” and “the” include plural referents unless thecontext clearly dictates otherwise. Thus, for example, reference to anitem includes reference to one or more items. The term “ones” refers toone, two, or more, and generally applies to the selection of some or allof a quantity. The term “plurality” refers to two or more of an item.The term “about” or “approximately” means that quantities, dimensions,sizes, formulations, parameters, shapes and other characteristics neednot be exact, but may be approximated and/or larger or smaller, asdesired, reflecting acceptable tolerances, conversion factors, roundingoff, measurement error and the like and other factors known to those ofskill in the art. The term “substantially” means that the recitedcharacteristic, parameter, or value need not be achieved exactly, butthat deviations or variations, including for example, tolerances,measurement error, measurement accuracy limitations and other factorsknown to those of skill in the art, may occur in amounts that do notpreclude the effect the characteristic was intended to provide.

Numerical data may be expressed or presented herein in a range format.It is to be understood that such a range format is used merely forconvenience and brevity and thus should be interpreted flexibly toinclude not only the numerical values explicitly recited as the limitsof the range, but also interpreted to include all of the individualnumerical values or sub-ranges encompassed within that range as if eachnumerical value and sub-range is explicitly recited. As an illustration,a numerical range of “about 1 to 5” should be interpreted to include notonly the explicitly recited values of about 1 to about 5, but shouldalso be interpreted to also include individual values and sub-rangeswithin the indicated range. Thus, included in this numerical range areindividual values such as 2, 3 and 4 and sub-ranges such as “about 1 toabout 3,” “about 2 to about 4” and “about 3 to about 5,” “1 to 3,” “2 to4,” “3 to 5,” etc. This same principle applies to ranges reciting onlyone numerical value (e.g., “greater than about 1”) and should applyregardless of the breadth of the range or the characteristics beingdescribed. A plurality of items may be presented in a common list forconvenience. However, these lists should be construed as though eachmember of the list is individually identified as a separate and uniquemember. Thus, no individual member of such list should be construed as ade facto equivalent of any other member of the same list solely based ontheir presentation in a common group without indications to thecontrary. Furthermore, where the terms “and” and “or” are used inconjunction with a list of items, they are to be interpreted broadly, inthat any one or more of the listed items may be used alone or incombination with other listed items. The term “alternatively” refers toselection of one of two or more alternatives, and is not intended tolimit the selection to only those listed alternatives or to only one ofthe listed alternatives at a time, unless the context clearly indicatesotherwise.

What is claimed is:
 1. A brake assembly comprising: a master cylinderassembly comprising a cylinder housing a piston comprising a pushrod; aknee coupled to the master cylinder by a pivot; a lever coupled to themaster cylinder assembly by the pivot and configured to compress theknee against the pushrod as the lever is advanced toward the mastercylinder assembly; and a plurality of removable inserts, a one of theplurality being coupled to the knee and disposed between the knee andthe pushrod, a remainder of the plurality being uncoupled from the knee,each of the plurality of the removable inserts comprising a cavityconfigured to receive at least a portion of the pushrod, a first insertof the plurality having the cavity a first radius away from the pivotwhen the insert is coupled to the knee, a second insert of the pluralityhaving the cavity a second radius away from the pivot when the insert iscoupled to the knee, the first radius being different from the secondradius.
 2. The brake assembly of claim 1 further comprising: anadjustment element comprising a base that engages the lever, a head thatengages the knee, and a length between the base and head, the lengthbeing adjustable, wherein the adjustment element is configured to pushthe knee toward the master cylinder assembly as the lever is advancedtoward the master cylinder assembly.
 3. The brake assembly of claim 2further comprising: a biasing element configured to compress the headagainst the knee.
 4. The brake assembly of claim 1 further comprising: aperch coupled to the master cylinder assembly, the perch surrounding anopening; and a clamp element configured to reduce an outer dimension ofthe opening.
 5. The brake assembly of claim 4 further comprising: aliner disposed between the perch and the opening.
 6. The brake assemblyof claim 4, wherein a first lateral surface of the perch defines a firstplane across a first end of the opening of the perch, a second lateralsurface defines a second plane across a second end of the opening of theperch, and the pivot is disposed between the first and second planes. 7.The brake assembly of claim 4, wherein a first lateral surface of theperch defines a first plane across a first end of the opening of theperch, a second lateral surface defines a second plane across a secondend of the opening of the perch, and the first plane is disposed betweenthe pivot and the second plane.
 8. The brake assembly of claim 1 furthercomprising a guard coupled to the master cylinder assembly, the guardcomprising a flange configured to cover a portion of the lever when thelever is in a first position and to not cover the portion when the leveris in a second position, the lever being closer to the master cylinderassembly in the second position than in the first position, wherein theflange has a clearance with the lever that is between about 1 mm andabout 2 mm.
 9. The brake assembly of claim 1, wherein an outer surfaceof the cylinder comprises a protrusion.
 10. The brake assembly of claim9, wherein the protrusion comprises a ridge that is substantiallyparallel with a longitudinal axis of the cylinder.
 11. The brakeassembly of claim 10, wherein the protrusion comprises two ridges thatare substantially parallel with one another.
 12. The brake assembly ofclaim 1, wherein the cavity of the first removable insert has a firstdepth that is different from a second depth of the cavity of the secondremovable insert.
 13. The brake assembly of claim 1, wherein the levercomprises a stop that engages a cap surface of the master cylinderassembly.
 14. The brake assembly of claim 13, wherein the cap portion isadjustable.
 15. The brake assembly of claim 1, wherein the one of theplurality is received in a recess disposed on a piston-facing surface ofthe knee.